Union with Christ our Prophet & Priest (Calvin's Institutes, Battles edition: pp. 494-503, vol. 1)

In Book 2, ch. 15 of the Institutes, Calvin explores the familiar-to-presbyterians analysis of Christ's redemptive work through the categories of prophet, king, and priest. He employs the doctrine of the believer's union with Christ in a couple of surprising ways to show how Christ's offices of prophet and priest are carried out in the Church today.

"[Christ] received anointing... for his whole body [i.e., the Church] that the power of the Spirit might be present in the continuing preaching of the Gospel." (p. 496) That is, Isaiah 61 is fulfilled not only in Luke 4, but, by virtue of the Church's mystical union with Christ, every time the Gospel is preached: in this sense, the prophetic office continues.

Then notice how he develops the doctrine of the priesthood of all believers: "Now, Christ plays the priestly role... to receive us as his companions in this great office (Rev. 1:6). For we who are defiled in ourselves, yet are priests in him, offer ourselves and our all to God, and freely enter the heavenly sanctuary that the sacrifices of prayers and praise that we bring may be acceptable and sweet-smelling before God." (p. 502) Calvin finds our priesthood exercised primarily in corporate worship, performed in heaven, the Temple/Tabernacle's archetype (Hebrews 9). Moreover, we are priests because we are united to our Great High Priest.